98 SE drops WAN & some LAN tcp/ip con’s

Win98 SE drops TCP/IP Inet connections at random (5-60 min) intervals and loses ability to explore LAN but affected machine can still be browsed and connected to from LAN. Am connecting through Linksys BEFSR41 DSL router. 2000 not affected but I think 95 OSR 2.1 may share affliction.
What causes this and how do I fix it?

Thanks